Cyber bullying
Cyber bullying is when a person or group of people bully and harass someone or a group of people such that their internet experience is unpleasant. Whilst cyber bullying can lead to cyber stalking and smear campaigns (and even to stalking and worse), cyber bullying in itself is often accidental and meant to be a bit of fun or else feeling that the person or people affected deserved it.
Cyber bullying is rarely prosecutable in a legal sense, although many schools prohibit it and can suspend or even expel a student who cyber bullies another student.